Light emitting diode display device

ABSTRACT

A display device according to an embodiment includes a substrate, a gate line and a data line on the substrate, a pixel connected to the gate line and the data line and including a thin film transistor (TFT) on the substrate, a planarization layer on the TFT, and a light emitting device including a first electrode and a second electrode, wherein the light emitting device comprises a first portion and a second portion opposite to the first portion, the first portion including the first and second electrodes, wherein the TFT comprises a gate electrode, a semiconductor layer, a source electrode, and a drain electrode, and wherein the first portion of the light emitting device is not overlapped with the TFT.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of co-pending U.S. patent applicationSer. No. 16/123,694 filed on Sep. 6, 2018, which is a Continuation ofU.S. patent application Ser. No. 15/794,741 filed on Oct. 26, 2017 (nowU.S. Pat. No. 10,090,335 issued on Oct. 2, 2018), which claims thepriority benefit under 35 U.S.C. § 119(a) to Korean Patent ApplicationNo. 10-2016-0141673 filed in the Republic of Korea on Oct. 28, 2016, allof these applications are hereby expressly incorporated by referenceinto the present application.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present disclosure relate to a display device, andmore particularly, to a light emitting diode display device.

Discussion of the Related Art

Display devices are being widely used as a display screen of notebookcomputers, tablet computers, smartphones, portable display devices, andportable information devices in addition to a display screen oftelevision (TVs) and monitors.

Liquid crystal display (LCD) devices and organic light emitting displaydevices display an image by using thin film transistors (TFTs) asswitching elements. Since the LCD devices cannot self-emit light, theLCD devices display an image by using light emitted from a backlightunit which is disposed under a liquid crystal display panel. Since theLCD devices include a backlight unit, a design of the LCD devices islimited, and luminance and a response time are reduced. Since theorganic light emitting display devices include an organic material, theorganic light emitting display devices are vulnerable to water, causinga reduction in reliability and lifetime.

Recently, research and development on light emitting diode displaydevices including a micro light emitting device are being done. Thelight emitting diode display devices have high image quality and highreliability, and thus, are attracting much attention as next-generationdisplay devices.

However, in a related art light emitting diode display device, much timeis taken in heating or cooling a substrate for bonding a light emittingdevice to a pixel circuit with a conductive adhesive in a process ofmounting a micro light emitting device on a TFT array substrate, and forthis reason, productivity is reduced.

SUMMARY OF THE INVENTION

Accordingly, the embodiments of the present disclosure are directed toprovide a light emitting diode display device that substantiallyobviates one or more problems due to limitations and disadvantages ofthe related art.

An aspect of the present disclosure is directed to provide a lightemitting diode display device in which a process time taken in a processof connecting a light emitting device to a pixel circuit is shortened.

Additional advantages and features of the disclosure will be set forthin part in the description which follows and in part will becomeapparent to those having ordinary skill in the art upon examination ofthe following or may be learned from practice of the disclosure. Theobjectives and other advantages of the disclosure may be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the disclosure, as embodied and broadly described herein, there is alight emitting diode display device including a pixel including adriving TFT on a substrate, a first layer covering the pixel, a concaveportion in the first layer, a light emitting device in the concaveportion and including a first electrode and a second electrode, a secondlayer covering the first layer and the light emitting device, a pixelelectrode electrically connected to the driving TFT and the firstelectrode of the light emitting device, and a common electrodeelectrically connected to the second electrode of the light emittingdevice, wherein the pixel electrode is on the second layer.

The concave portion may be concavely from the first layer.

The pixel electrode may be electrically connected to a source electrodeof the driving TFT through a first circuit contact hole in the first andsecond layers and may be electrically connected to the first electrodeof the light emitting device through a first electrode contact hole inthe second layer.

The common electrode may be electrically connected to the secondelectrode of the light emitting device through a second electrodecontact hole in the second layer.

In another aspect of the present disclosure, there is a display devicecomprising: a first substrate; a pixel including a driving thin filmtransistor (TFT) on the first substrate; a first layer covering thepixel; a concave portion in the first layer; a light emitting device inthe concave portion, the light emitting device including a firstelectrode and a second electrode; a second layer covering the firstlayer and the light emitting device; a pixel electrode electricallyconnected to the driving TFT and the first electrode of the lightemitting device; a common electrode electrically connected to the secondelectrode of the light emitting device; and a second substrate, whereinthe first and second electrodes in the concave portion are disposed toface the second substrate without being disposed to face a floor surfaceof the concave portion.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure are byexample and explanatory and are intended to provide further explanationof the disclosure as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiments of the disclosure andtogether with the description serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is a diagram for describing a configuration of a light emittingdiode display device according to an embodiment of the presentdisclosure;

FIG. 2 is a circuit diagram for describing a configuration of a pixelillustrated in FIG. 1;

FIG. 3 is a cross-sectional view for describing a connection structureof a driving TFT and a light emitting device in one pixel illustrated inFIG. 2;

FIG. 4 is a cross-sectional view for describing the light emittingdevice illustrated in FIG. 3;

FIG. 5 is a diagram for describing a modification embodiment of aconcave portion illustrated in FIG. 3;

FIG. 6 is a diagram for describing a light emitting diode display deviceaccording to another embodiment of the present disclosure; and

FIGS. 7 to 13 are diagrams for describing a light emitting diode displaydevice according to another embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the example embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Advantages and features of the present disclosure, and implementationmethods thereof will be clarified through following embodimentsdescribed with reference to the accompanying drawings. The presentdisclosure may, however, be embodied in different forms and should notbe construed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the present disclosureto those skilled in the art. Furthermore, the present disclosure is onlydefined by scopes of the claims.

A shape, a size, a ratio, an angle, and a number disclosed in thedrawings for describing embodiments of the present disclosure are merelyan example, and thus, the present disclosure is not limited to theillustrated details. Like reference numerals refer to like elementsthroughout. In the following description, when the detailed descriptionof the relevant known technology is determined to unnecessarily obscurethe important point of the present disclosure, the detailed descriptionwill be omitted.

In an instance where ‘comprise’, ‘have’, and ‘include’ described in thepresent specification are used, another part may be added unless ‘only˜’is used. The terms of a singular form may include plural forms unlessreferred to the contrary.

In construing an element, the element is construed as including an errorrange although there may be no explicit description.

In describing a position relationship, for example, when a positionrelation between two parts is described as ‘on˜’, ‘over˜’, ‘under˜’ and‘next˜’, one or more other parts may be disposed between the two partsunless ‘just’ or ‘direct’ is used.

In describing a time relationship, for example, when the temporal orderis described as ‘after˜’, ‘subsequent˜’, ‘next˜’ and ‘before˜’, aninstance which is not continuous may be included unless ‘just’ or‘direct’ is used.

It will be understood that, although the terms “first”, “second”, etc.may be used herein to describe various elements, these elements shouldnot be limited by these terms. These terms are only used to distinguishone element from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure.

A first horizontal axis direction, a second horizontal axis direction,and a vertical axis direction should not be construed as only ageometric relationship where a relationship therebetween is strictlyvertical, and may denote having a broader directionality within a scopewhere elements of the present disclosure operate functionally.

The term “at least one” should be understood as including any and allcombinations of one or more of the associated listed items. For example,the meaning of “at least one of a first item, a second item, and a thirditem” denotes the combination of all items proposed from two or more ofthe first item, the second item, and the third item as well as the firstitem, the second item, or the third item.

Features of various embodiments of the present disclosure may bepartially or overall coupled to or combined with each other, and may bevariously inter-operated with each other and driven technically as thoseskilled in the art can sufficiently understand. The embodiments of thepresent disclosure may be carried out independently from each other, ormay be carried out together in a co-dependent relationship.

Hereinafter, example embodiments of a light emitting diode displaydevice according to the present disclosure will be described in detailwith reference to the accompanying drawings. In the specification, inadding reference numerals for elements in each drawing, it should benoted that like reference numerals already used to denote like elementsin other drawings are used for elements wherever possible. In thefollowing description, when the detailed description of the relevantknown function or configuration is determined to unnecessarily obscurethe important point of the present disclosure, the detailed descriptionwill be omitted.

FIG. 1 is a diagram for describing a configuration of a light emittingdiode display device according to an embodiment of the presentdisclosure, and FIG. 2 is a circuit diagram for describing aconfiguration of a pixel illustrated in FIG. 1. All the components ofthe light emitting diode display device according to all embodiments ofthe present disclosure are operatively coupled and configured.

Referring to FIGS. 1 and 2, the light emitting diode display deviceaccording to an embodiment of the present disclosure may include a firstsubstrate 100, a plurality of light emitting devices 300, and a secondsubstrate 500.

The first substrate 100 may be a thin film transistor (TFT) arraysubstrate and may be formed of glass, a plastic material, and/or thelike. The first substrate 100 according to an embodiment may include adisplay area (or an active area) AA and a non-display area (or aninactive area) IA.

The display area AA may be provided in a portion other than an edge ofthe first substrate 100. The display area AA may be defined as an areawhere a pixel array displaying an image is provided.

The non-display area IA may be provided in a portion other than thedisplay area AA provided on the substrate 100 and may be defined as theedge of the first substrate 100 surrounding the display area AA. Thenon-display area IA may be a peripheral portion outside the display areaAA and cannot display an image unlike the display area AA, and moreover,the non-display area IA may be defined as an area where lines andcircuits for driving the pixel array are disposed. For example, thenon-display area IA may include a first non-display area defined in aperipheral portion outside an upper side of the display area AA, asecond non-display area defined in a peripheral portion outside a lowerside of the display area AA, a third non-display area defined in aperipheral portion outside a left side of the display area AA, and afourth non-display area defined in a peripheral portion outside a rightside of the display area AA.

The first substrate 100 according to an embodiment may include aplurality of gate lines GL, a plurality of data lines DL, a plurality ofdriving power lines PL, a plurality of common power lines CL, aplurality of pixels SP, and a plurality of concave portions 130.

The plurality of gate lines GL may be provided on the first substrate100, may long extend along a first horizontal axis direction X of thefirst substrate 100, may be arranged along a second horizontal axisdirection Y, and may be spaced apart from each other by a certaininterval. In this instance, the first horizontal axis direction X may bedefined as a direction parallel to a long side length direction of thefirst substrate 100, and the second horizontal axis direction Y may bedefined as a direction parallel to a short side length direction of thefirst substrate 100. Alternatively, each of the first horizontal axisdirection X and the second horizontal axis direction Y may be defined asa direction opposite thereto.

The plurality of data lines DL may be provided on the first substrate100 to intersect the plurality of gate lines GL, may long extend alongthe second horizontal axis direction Y of the first substrate 100, maybe arranged along the first horizontal axis direction X, and may bespaced apart from each other by a certain interval.

The plurality of driving power lines PL may be provided on the firstsubstrate 100 in parallel with the plurality of data lines DL and may beformed along with the plurality of data lines DL. Each of the pluralityof driving power lines PL may supply a pixel driving power, suppliedfrom the outside, to an adjacent pixel SP.

The plurality of driving power lines PL may be connected in common toone first driving power common line provided in the first non-displayarea of the first substrate 100 in parallel with the gate line GL. Theone first driving power common line may distribute the pixel drivingpower, supplied from the outside, to the plurality of driving powerlines PL. The first driving power common line may be provided on thesame layer as the gate line GL, electrically disconnected from each ofthe plurality of data lines DL, and electrically connected to an end ofeach of the plurality of driving power lines PL through a via hole.

In addition, the pixel driving power may be supplied to one end andanother end of each of the plurality of driving power lines PL. To thisend, the one end of each of the plurality of driving power lines PL maybe connected to the one first driving power common line provided in thefirst non-display area of the first substrate 100, and the other end ofeach of the plurality of driving power lines PL may be connected to theone second driving power common line provided in the second non-displayarea of the first substrate 100. In this instance, according to anembodiment of the present disclosure, the pixel driving power may beapplied to an upper end and a lower end of each of the plurality ofdriving power lines PL through the first and second driving power commonlines, thereby minimizing the voltage drop of the pixel driving powerwhich occurs in each of the plurality of driving power lines PL due to aposition-based line resistance of each of the plurality of driving powerlines PL.

The first and second driving power common lines may be provided on thesame layer as the plurality of gate lines GL and may be electricallyconnected to the end of each of the plurality of driving power lines PLthrough the via hole.

The plurality of common power lines CL may be arranged on the firstsubstrate 100 in parallel with the plurality of gate lines GL and may beformed along with the plurality of gate lines GL. Each of the pluralityof common power lines CL may supply a common power, supplied from theoutside, to an adjacent pixel SP. Each of the plurality of common powerlines CL may be individually supplied with the common power from a paneldriver 900. In this instance, the panel driver 900 may individuallycontrol a voltage level of the common power supplied to each of theplurality of common power lines CL to compensate for an electricalcharacteristic of the light emitting devices 300 and/or an electricalcharacteristic change of a below-described driving TFT.

In addition, the plurality of common power lines CL may be connected incommon to a common power supply line provided in at least one of thethird and fourth non-display areas of the first substrate 100. Thecommon power supply line may distribute the common power, supplied fromthe outside, to the plurality of common power lines CL. The common powersupply line may be provided on the same layer as the data lines DL,electrically disconnected from each of the plurality of gate lines GL,and electrically connected to an end of each of the plurality of commonpower lines CL through a via hole.

The plurality of pixels SP may be respectively provided in a pluralityof pixel areas defined by intersections of the gate lines GL and thedata lines DL. Each of the plurality of pixels SP may be an areacorresponding to a minimum unit where light is actually emitted, and maybe defined as a subpixel. At least three adjacent pixels SP mayconfigure one unit pixel UP for displaying colors. For example, the oneunit pixel UP may include a red pixel SP1, a green pixel SP2, and a bluepixel SP3 which are adjacent to each other, and may further include awhite pixel for enhancing luminance.

Each of the plurality of pixels SP may include a pixel circuit PC.

Each pixel circuit PC may be provided in a circuit area defined in acorresponding pixel SP and may be connected to a gate line GL, a dataline DL, and a driving power line PL which are adjacent thereto. Eachpixel circuit PC may control a current flowing in the light emittingdevice 300 according to a data signal supplied through the data line DLin response to a scan pulse supplied through the gate line GL, based onthe pixel driving power supplied through the driving power line PL. Thepixel circuit PC according to an embodiment may include a switching TFTT1, a driving TFT T2, and a capacitor Cst.

For each pixel SP, switching TFT T1 may include a gate electrodeconnected to the gate line GL, a first electrode connected to the dataline DL, and a second electrode connected to a gate electrode N1 of thedriving TFT T2. In this instance, each of the first and secondelectrodes of the switching TFT T1 may be a source electrode or a drainelectrode according to a direction of a current. The switching TFT T1may be turned on according to the scan pulse supplied through the gateline GL and may supply the data signal, supplied through the data lineDL, to the driving TFT T2.

The driving TFT T2 may be turned on by a voltage supplied through theswitching TFT T1 and/or a voltage of the capacitor Cst to control theamount of current flowing from the driving power line PL to the lightemitting device 300. To this end, the driving TFT T2 according to anembodiment may include a gate electrode connected to the secondelectrode N1 of the switching TFT T1, a drain electrode connected to thedriving power line PL, and a source electrode connected to the lightemitting device 300. The driving TFT T2 may control a data currentflowing from the driving power line PL to the light emitting device 300according to the data signal supplied through the switching TFT T1,thereby allowing the light emitting device 300 to emit light havingbrightness proportional to the data signal.

The capacitor Cst may be provided in an overlap area between the gateelectrode N1 and the source electrode of the driving TFT T2, may store avoltage corresponding to the data signal supplied to the gate electrodeof the driving TFT T2, and may turn on the driving TFT T2 with thestored voltage.

Each of the plurality of concave portions 130 may be provided in anemissive area defined in each of the plurality of pixels SP and mayaccommodate the light emitting device 300. Each of the plurality ofconcave portions 130 according to an embodiment may be providedconcavely from a first planarization layer (or a passivation layer) 110(e.g., see FIG. 3) provided on the first substrate 100 to cover thepixel SP, namely, the pixel circuit PC. For example, each of theplurality of concave portions 130 may have a groove shape or a cup shapehaving a certain depth from a top 110 a (e.g., see FIG. 3) of the firstplanarization layer 110. Each of the plurality of concave portions 130may be concavely provided in the first planarization layer 110 and mayaccommodate the light emitting device 300, thereby minimizing anincrease in a thickness of a display device caused by a thickness (or adepth) of the light emitting device 300.

Each of the plurality of light emitting devices 300 may be accommodatedinto the concave portion 130 provided in a corresponding pixel SP of theplurality of pixels SP. Each of the plurality of light emitting devices300 may be connected to the pixel circuit PC of a corresponding pixelSP, and thus, may emit light having brightness proportional to a currentflowing from the pixel circuit PC (i.e., the driving TFT T2) to thecommon power line CL. Each of the light emitting devices 300 accordingto an embodiment may be a light emitting diode device or a lightemitting diode chip which emits one of red light, green light, bluelight, and white light. For example, the light emitting device 300 maybe a micro light emitting diode device or a micro light emitting diodechip. In this instance, the micro light emitting diode chip may have ascale of 1 μm to 100 μm, but is not limited thereto. In otherembodiments, the micro light emitting diode chip may have a size whichis smaller than a size of an emissive area other than an area occupiedby the pixel circuit PC in a corresponding pixel area.

The plurality of light emitting devices 300 according to an embodimentmay each include a first electrode E1 (e.g., see FIG. 3) connected tothe source electrode of the driving TFT T2 through a first circuitcontact hole CCH1, a second electrode E2 (e.g., see FIG. 3) connected tothe common power line CL through a second circuit contact hole CCH2, anda light emitting layer provided between the first electrode E1 and thesecond electrode E2. Each of the plurality of light emitting devices 300may be accommodated into the concave portion 130 and may be exposed in adirection toward an upper portion of the concave portion 130 withoutbeing covered by the concave portion 130. That is, each of the pluralityof light emitting devices 300 may include a first portion where thefirst and second electrodes E1 and E2 are provided and a second portionopposite to the first portion, and may be accommodated into the concaveportion 130 so that the first portion is disposed relatively fartherapart from a floor surface 130 a (e.g., see FIG. 3) of the concaveportion 130 than the second portion and is adjacent to an image displaysurface. For example, when it is assumed that the first portion of thelight emitting device 300 is an upper portion of the light emittingdevice 300 and the second portion of the light emitting device 300 is alower portion of the light emitting device 300, in the presentembodiment, the light emitting device 300 may be accommodate into theconcave portion 130 without a top and a bottom of the light emittingdevice 300 being reversed therebetween, and thus, a process of reversingthe top and the bottom of the light emitting device 300 may be omittedin comparison with the related art. In embodiments of the presentdisclosure, a distance between the first portion to the floor surface116 a of the concave portion 116 may be greater than a distance betweenthe second portion to the floor surface 116 a of the concave portion116. A structure of each of the light emitting devices 300 will bedescribed below.

The second substrate 500 may be disposed to cover the first substrate100 and may be defined as an opposite substrate, a color filter arraysubstrate, or an encapsulation substrate. The second substrate 500 maybe opposite-bonded to the first substrate 100 by a sealant surroundingthe display area AA of the first substrate 100.

In addition, the light emitting diode display device according to anembodiment of the present disclosure may further include a scan drivingcircuit 700 and a panel driver 900.

The scan driving circuit 700 may generate the scan pulse according to agate control signal input from the panel driver 900 and may supply thescan pulse to the gate lines GL. The scan driving circuit 700 may bebuilt into the third non-display area of the first substrate 100 througha process which is the same as a process of forming the TFTs provided ineach pixel SP. For example, the scan driving circuit 700 may be providedin a left and/or right non-display area with respect to the display areaAA, but is not limited thereto. In other embodiments, the scan drivingcircuit 700 may be provided in an arbitrary non-display area whichenables the scan pulse to be supplied to the gate lines GL.

Optionally, the scan driving circuit 700 may be manufactured as adriving integrated circuit (IC) type. In this instance, the scan drivingcircuit 700 according to an embodiment may be mounted in the thirdand/or fourth non-display area of the first substrate 100 so as to beconnected to the plurality of gate lines in a one-to-one correspondencerelationship. According to another embodiment, the scan driving circuit700 may be mounted on a gate flexible circuit film, and in thisinstance, the gate flexible circuit film may be attached on a gate padpart provided in the third and/or fourth non-display area of the firstsubstrate 100, whereby the scan driving circuit 700 may be connected tothe plurality of gate lines GL through the gate flexible circuit filmand the gate pad part in a one-to-one correspondence relationship.

The panel driver 900 may be connected to a pad part provided in thefirst non-display area of the first substrate 100 and may display animage, corresponding to image data supplied from a display drivingsystem, on the display area AA. The panel driver 900 according to anembodiment may include a plurality of data flexible circuit films 910, aplurality of data driving ICs 930, a printed circuit board (PCB) 950, atiming controller 970, and a power circuit 990.

Each of the plurality of data flexible circuit films 910 may be attachedon the pad part of the first substrate 100 through a film attachmentprocess.

Each of the plurality of data driving ICs 930 may be individuallymounted on a corresponding data flexible circuit film of the pluralityof data flexible circuit films 910. The data driving ICs 930 may receivepixel data and a data control signal supplied from the timing controller970, convert the pixel data into analog data voltages by pixelsaccording to the data control signal, and respectively supply the analogdata voltages to the data lines DL.

The PCB 950 may be connected to the plurality of data flexible circuitfilms 910. The PCB 950 may support the timing controller 970 and thepower circuit 990 and may transfer signals and power between theelements of the panel driver 900.

The timing controller 970 may be mounted on the PCB 950 and may receiveimage data and a timing synchronization signal supplied from the displaydriving system through a user connector provided on the PCB 950. Thetiming controller 970 may align the image data according to a pixelarrangement structure of the display area AA based on the timingsynchronization signal to generate pixel data and may supply thegenerated pixel data to the data driving ICs 930. Also, the timingcontroller 970 may generate the data control signal and the gate controlsignal, based on the timing synchronization signal and may control adriving timing of each of the data driving ICs 930 and the scan drivingcircuit 700.

The power circuit 990 may be mounted on the PCB 950 and may generatevarious voltages necessary for displaying an image on the display areaAA by using an input power received from the outside to supply each ofthe voltages to a corresponding element.

In addition, the panel driver 900 may further include a control boardconnected to the PCB 950. In this instance, the timing controller 970and the power circuit 990 may be mounted on the control board withoutbeing mounted on the PCB 950. Accordingly, the PCB 950 may perform onlya function of transferring signals and power between the plurality ofdata flexible circuit films 910 and the control board.

In the light emitting diode display device according to an embodiment ofthe present disclosure, since each of the light emitting devices 300 isaccommodated into the concave portion 130 provided in the emissive areaof a corresponding pixel SP, a misalignment of the light emittingdevices 300 mounted on the pixels SP is prevented or reduced fromoccurring in a mounting process performed for the light emitting devices300, and an alignment precision of the light emitting devices 300 isimproved. Particularly, in the light emitting diode display deviceaccording to an embodiment of the present disclosure, since theelectrodes of each of the light emitting devices 300 are greatly spacedapart from the floor surface 130 a of the concave portion 130 and areconnected to the pixel circuit PC through the contract holes CCH1 andCCH2, a connection process of connecting the light emitting device 300and the pixel circuit PC is simplified, and a process time taken inconnecting the light emitting device 300 and the pixel circuit PC isshortened.

FIG. 3 is a cross-sectional view for describing a connection structureof a driving TFT and a light emitting device in one pixel illustrated inFIG. 2, and FIG. 4 is a cross-sectional view for describing the lightemitting device illustrated in FIG. 3.

Referring to FIGS. 3 and 4 along with FIG. 2, a light emitting diodedisplay device according to the present embodiment may include aplurality of pixels SP, a first planarization layer 110, a concaveportion 130, a light emitting device 300, a second planarization layer140, a pixel electrode AE, and a common electrode CE.

The plurality of pixels SP may each include a pixel circuit PC includinga driving TFT T2 provided on a first substrate 100.

The driving TFT T2 may include a gate electrode GE, a semiconductorlayer SCL, an ohmic contact layer OCL, a source electrode SE, and adrain electrode DE.

The gate electrode GE may be formed on the first substrate 100 alongwith the gate lines GL. The gate electrode GE may be covered by a gateinsulation layer 103.

The gate insulation layer 103 may be formed of a single layer or amultilayer including an inorganic material and may be formed of siliconoxide (SiOx) silicon nitride (SiNx), and/or the like.

The semiconductor layer SCL may be provided in a predetermined pattern(or island) type on the gate insulation layer 103 to overlap the gateelectrode GE. The semiconductor layer SCL may be formed of asemiconductor material including one of amorphous silicon,polycrystalline silicon, oxide, and an organic material, but is notlimited thereto.

The ohmic contact layer OCL may be provided in a predetermined pattern(or island) type on the semiconductor layer SCL. In this instance, theohmic contact layer OCL is for an ohmic contact between thesemiconductor layer SCL and the source and drain electrodes SE and DEand may be omitted.

The source electrode SE may be formed on one side of the ohmic contactlayer OCL to overlap one side of the semiconductor layer SCL. The sourceelectrode SE may be formed along with the data lines DL and the drivingpower lines PL.

The drain electrode DE may be formed on the other side of the ohmiccontact layer OCL to overlap the other side of the semiconductor layerSCL and may be spaced apart from the source electrode SE. The drainelectrode DE may be formed along with the source electrode SE and maybranch or protrude from an adjacent driving power line PL.

In addition, the switching TFT T1 configuring the pixel circuit PC maybe formed in a structure which is the same as that of the driving TFTT2. In this instance, the gate electrode of the switching TFT T1 maybranch or protrude from the gate line GL, the first electrode of theswitching TFT T1 may branch or protrude from the data line DL, and thesecond electrode of the switching TFT T1 may be connected to the gateelectrode GE of the driving TFT T2 through a via hole provided in thegate insulation layer 103.

The pixel circuit PC may be covered by an interlayer insulation layer105. The interlayer insulation layer 105 may be provided all over thefirst substrate 100 to cover the pixel circuit PC including the drivingTFT T2. The interlayer insulation layer 105 according to an embodimentmay be formed of an inorganic material, such as SiOx or SiNx, or anorganic material such as benzocyclobutene or photo acryl. The interlayerinsulation layer 105 may not be provided.

The first planarization layer (or the passivation layer) 110 may beprovided all over the first substrate 100 to cover the pixel SP (i.e.,the pixel circuit PC), or may be provided all over the first substrate100 to cover the interlayer insulation layer 105. The firstplanarization layer 110 may protect the pixel circuit PC including thedriving TFT T2 and may provide a planar surface on the interlayerinsulation layer 105. The first planarization layer 110 according to anembodiment may be formed of an organic material such as benzocyclobuteneor photo acryl, and particularly, may be formed of photo acryl forconvenience of a process.

Each concave portion 130 may be provided in an emissive area defined inthe corresponding pixel SP and may accommodate the corresponding lightemitting device 300. In this instance, the emissive area of the pixel SPmay be defined as an area including an area overlapping the lightemitting device 300, and more particularly, may be defined as an areaother than a circuit area with the pixel circuit PC provided therein ina pixel area.

The concave portion 130 according to an embodiment may be providedconcavely from the first planarization layer 110, which is provided onthe first substrate 100 to cover the pixel circuit PC, to have a certaindepth D1. In this instance, the concave portion 130 may be providedconcavely from the top 110 a of the first planarization layer 110 tohave a depth corresponding to a thickness (or a total height) of thelight emitting device 300. In this instance, the floor surface 130 a ofthe concave portion 130 may be formed by removing a portion of the firstplanarization layer 110, a whole portion of the first planarizationlayer 110, the whole portion of the first planarization layer 110 and aportion of the interlayer insulation layer 105, or the whole portion ofthe first planarization layer 110 and the interlayer insulation layer105, and a whole portion of the gate insulation layer 103 which overlapthe emissive area of the pixel SP, in order to have the depth D1 whichis set based on the thickness of the light emitting device 300. Forexample, the concave portion 130 may be provided to have a depth of 2 μmto 6 μm from the top 110 a of the first planarization layer 110. Theconcave portion 130 may have a groove or cup shape having a size of thefloor surface 130 a which is wider than a second portion 300 b of thelight emitting device 300.

The light emitting device 300 according to an embodiment may beaccommodated into the concave portion 130 provided in the pixel SP andmay be connected to the pixel circuit PC. The light emitting device 300may include a first portion 300 a, including the first and secondelectrodes E1 and E2 connected to the pixel circuit PC, and a secondportion 300 b opposite to the first portion 300 a. In this instance, thefirst portion 300 a of the light emitting device 300 may be disposedrelatively farther away from the floor surface 130 a of the concaveportion 130 than the second portion 300 b. That is, in the lightemitting device 300, the first and second electrodes E1 and E2 providedin the first portion 300 a may be disposed to face the second substrate500 without being disposed to face the inside of the concave portion130, namely, the floor surface 130 a of the concave portion 130. In thisinstance, the first portion 300 a of the light emitting device 300 mayhave a size which is smaller than the second portion 300 b, and in thisinstance, the light emitting device 300 may have a cross-sectionalsurface having a trapezoid shape. The first and second electrodes E1 andE2 of the light emitting device 130 may have differences in heightrelative to the floor surface 116 a of the concave portion 116. Inembodiments of the present disclosure, a height of the light emittingdevice 130 may be greater than a depth of the concave portion 116, butin other embodiments, the height of the light emitting device 130 may beless than the depth of the concave portion 116. Also, heights of thefirst electrode E1 and the second electrode E2 may be the same, and thepixel electrode pattern AE and the common electrode pattern CE may beco-planar.

The light emitting device 300 according to an embodiment may include alight emitting layer EL, the first electrode E1, and the secondelectrode E2.

The light emitting layer EL may emit light according to a recombinationof an electron and a hole based on a current flowing between the firstelectrode E1 and the second electrode E2. The light emitting layer ELaccording to an embodiment may include a first semiconductor layer 310,an active layer 330, and a second semiconductor layer 350.

The first semiconductor layer 310 may supply an electron to the activelayer 330. The first semiconductor layer 310 according to an embodimentmay be formed of an n-GaN-based semiconductor material, and examples ofthe n-GaN-based semiconductor material may include GaN, AlGaN. InGaN,AlInGaN, etc. In this instance, silicon (Si), germanium (Ge), selenium(Se), tellurium (Te), or carbon (C) may be used as impurities used fordoping of the first semiconductor layer 310.

The active layer 330 may be provided on one side of the firstsemiconductor layer 310. The active layer 330 may have a multi quantumwell (MQW) structure which includes a well layer and a barrier layerwhich is higher in band gap than the well layer. The active layer 330according to an embodiment may have an MQW structure of InGaN/GaN or thelike.

The second semiconductor layer 350 may be provided on the active layer330 and may supply a hole to the active layer 330. The secondsemiconductor layer 350 according to an embodiment may be formed of ap-GaN-based semiconductor material, and examples of the p-GaN-basedsemiconductor material may include GaN, AlGaN. InGaN, AlInGaN, etc. Inthis instance, magnesium (Mg), zinc (Zn), or beryllium (Be) may be usedas impurities used for doping of the second semiconductor layer 350.

In addition, the first semiconductor layer 310, the active layer 330,and the second semiconductor layer 350 may be provided in a structure ofbeing sequentially stacked on a semiconductor substrate. In thisinstance, the semiconductor substrate may include a semiconductormaterial included in a sapphire substrate or a silicon substrate. Thesemiconductor substrate may be used as a growth semiconductor substratefor growing each of the first semiconductor layer 310, the active layer330, and the second semiconductor layer 350, and then, may be separatedfrom the first semiconductor layer 310 through a substrate separationprocess. In this instance, the substrate separation process may be alaser lift-off process or a chemical lift-off process. Therefore, sincethe growth semiconductor substrate is removed from the light emittingdevice 300, the light emitting device 300 has a thin thickness, andthus, may be accommodated into the concave portion 130 provided in thepixel SP.

The first electrode E1 may be provided on the second semiconductor layer350. The first electrode E1 may be connected to the source electrode SEof the driving TFT T2.

The second electrode E2 may be provided on the other side of the firstsemiconductor layer 310 and may be electrically disconnected from theactive layer 330 and the second semiconductor layer 350. The secondelectrode E2 may be connected to the common power line CL.

Each of the first and second electrodes E1 and E2 according to anembodiment may be formed of a material including one or more materialsof a metal material, such as gold (Au), tungsten (W), platinum (Pt),iridium (Ir), silver (Ag), copper (Cu), nickel (Ni), titanium (Ti), orchromium (Cr), and an alloy thereof. In other embodiments, each of thefirst and second electrodes E1 and E2 may be formed of a transparentconductive material, and examples of the transparent conductive materialmay include indium tin oxide (ITO), indium zinc oxide (IZO), etc.However, the present embodiment is not limited thereto.

The light emitting device 300 may emit the light according to therecombination of the electron and the hole based on the current flowingbetween the first electrode E1 and the second electrode E2. In thisinstance, the light emitted from the light emitting device 300 may passthrough the first and second electrodes E1 and E2 and may be output tothe outside, thereby displaying an image. In other words, the lightemitted from the light emitting device 300 may pass through the firstand second electrodes E1 and E2 and may be output in a second directionopposite to a first direction toward the floor surface 130 a of theconcave portion 130, thereby displaying an image.

The light emitting device 300 may be adhered to the floor surface 130 aof the concave portion 130 by an adhesive member 305.

The adhesive member 305 may be disposed between the floor surface 130 aof the concave portion 130 and the light emitting device 300 and mayattach the light emitting device 300 on the floor surface 130 a of theconcave portion 130. For example, the adhesive member 305 may beattached (coated) on the second portion 300 b of the light emittingdevice 300 (i.e., a back surface of the first semiconductor layer 310),and thus, in a mounting process of mounting the light emitting device300 onto the concave portion 130, the adhesive member 305 may be adheredto the floor surface 130 a of the concave portion 130. As anotherexample, the adhesive member 305 may be dotted onto the floor surface130 a of the concave portion 130 and may be spread by pressure which isapplied thereto in a mounting process performed for the light emittingdevice 300, and thus, may be adhered to the second portion 300 b of thelight emitting device 300 (i.e., the back surface of the firstsemiconductor layer 310). Therefore, the light emitting device 300mounted on the concave portion 130 may be primarily position-fixed bythe adhesive member 305. Accordingly, according to an embodiment of thepresent disclosure, the mounting process for the light emitting device300 may be performed in a method of simply attaching the light emittingdevice 300 on the floor surface 130 a of the concave portion 130, andthus, a mounting process time taken in performing the mounting processfor the light emitting device 300 is shortened.

A mounting process for a light emitting device according to anembodiment may further include a process of mounting a red lightemitting device on each of red pixels SP1, a process of mounting a greenlight emitting device on each of green pixels SP2, and a process ofmounting a blue light emitting device on each of blue pixels SP3, andmoreover, may further include a process of mounting a white lightemitting device on each of white pixels.

The mounting process for the light emitting device according to anembodiment may include only a process of mounting the white lightemitting device on each of pixels. In this instance, the first substrate100 or the second substrate 500 may include a color filter layeroverlapping each pixel. The color filter layer may transmit only light,having a wavelength of a color corresponding to a corresponding pixel,of white light.

The mounting process for the light emitting device according to anembodiment may include only a process of mounting a first-color lightemitting device on each pixel. In this instance, the first substrate 100or the second substrate 500 may include a wavelength conversion layerand the color filter layer overlapping each pixel. The wavelengthconversion layer may emit light of a second color, based on some oflight incident from the first-color light emitting device. The colorfilter layer may transmit only light, having a wavelength of a colorcorresponding to a corresponding pixel, of white light based on acombination of light of the first color and the light of the secondcolor. In this instance, the first color may be blue, and the secondcolor may be yellow.

The second planarization layer 140 may be provided on the firstplanarization layer 110 to cover the light emitting device 130. Thesecond planarization layer 140 may be provided all over the firstsubstrate 100 to cover a top 110 a of the first planarization layer 110,a peripheral portion of the light emitting device 300 disposed in theconcave portion 130, and a top of the light emitting device 300. In thisinstance, the second planarization layer 140 may be provided to have athickness which enables the second planarization layer 140 to bury aperipheral space of the light emitting device 300 disposed in theconcave portion 130 and cover the first and second electrodes E1 and E2of the light emitting device 300 disposed in the concave portion 130.The second planarization layer 140 may provide a planarization surfaceof the first planarization layer 110. Also, the second planarizationlayer 140 may bury the peripheral space of the light emitting device 300disposed in the concave portion 130 to secondarily fix the lightemitting device 300 which is primarily fixed to the concave portion 130by the adhesive member 305. In embodiments of the present disclosure, aportion of the second planarization layer 140 may be disposed betweenthe first electrode E1 and the second electrode E2.

The pixel electrode AE may be electrically connected to the driving TFTT2 and the first electrode E1 of the light emitting device 300 and maybe defined as an anode electrode. The pixel electrode AE may be providedon the second planarization layer 140 overlapping the driving TFT T2 andthe first electrode E1 of the light emitting device 300. The pixelelectrode AE may be electrically connected to the source electrode SE ofthe driving TFT T2 through a first circuit contact hole CCH1 which isprovided to pass through the interlayer insulation layer 105, the firstplanarization layer 110, and the second planarization layer 140, and maybe electrically connected to the first electrode E1 of the lightemitting device 300 through a first electrode contact hole ECH1 providedin the second planarization layer 140. Therefore, the first electrode E1of the light emitting device 300 may be electrically connected to thesource electrode SE of the driving TFT T2 through the pixel electrodeAE. In this manner, if the light emitting diode display device has a topemission structure, the pixel electrode AE may be formed of atransparent conductive material, and if the light emitting diode displaydevice has a bottom emission structure, the pixel electrode AE may beformed of a light reflection conductive material. In this instance, thetransparent conductive material may be indium tin oxide (ITO), indiumzinc oxide (IZO), or the like, but is not limited thereto. The lightreflection conductive material may be Al, Ag, Au, Pt, Cu, or the like,but is not limited thereto. The pixel electrode AE including the lightreflection conductive material may be formed of a single layer includingthe light reflection conductive material or a multilayer including aplurality of the single layers which are stacked.

The first circuit contact hole CCH1 may be provided in the first andsecond planarization layers 110 and 140 and the interlayer insulationlayer 105 overlapping a portion of the source electrode SE of thedriving TFT T2 and may expose the portion of the source electrode SE ofthe driving TFT T2. The first circuit contact hole CCH1 may be providedby removing the first and second planarization layers 110 and 140 andthe interlayer insulation layer 105 overlapping the portion of thesource electrode SE of the driving TFT T2 through a hole patterningprocess using a photolithography process and an etching process.

The first electrode contact hole ECH1 may expose a portion or a wholeportion of the first electrode E1 of the light emitting device 300 andmay be provided along with the first circuit contact hole CCH1. Thefirst electrode contact hole ECH1 may be provided by removing the secondplanarization layer 140 overlapping the portion or the whole portion ofthe first electrode E1 of the light emitting device 300 through a holepatterning process using a photolithography process and an etchingprocess. In this instance, the first circuit contact hole CCH1 and thefirst electrode contact hole ECH1 may have different depths.Accordingly, in the present embodiment, a mask pattern may be formed onthe second planarization layer 140 through a photolithography processusing a half tone mask, and the first circuit contact hole CCH1 and thefirst electrode contact hole ECH1 may be simultaneously formed throughan etching process using the mask pattern.

The common electrode CE may be electrically connected to the secondelectrode E2 of the light emitting device 300 and the common power lineCL and may be defined as a cathode electrode. The common electrode CEmay be provided on the second planarization layer 140 overlapping thesecond electrode E2 of the light emitting device 300 and the commonpower line CL. In this instance, the common electrode CE may be formedof a material which is the same as that of the pixel electrode AE. Thecommon electrode CE may be electrically connected to the common powerline CL through a second circuit contact hole CCH2 which is provided topass through the gate insulation layer 103, the interlayer insulationlayer 105, the first planarization layer 110, and the secondplanarization layer 140, and may be electrically connected to the secondelectrode E2 of the light emitting device 300 through a second electrodecontact hole ECH2 provided in the second planarization layer 140.Therefore, the second electrode E2 of the light emitting device 300 maybe electrically connected to the common power line CL through the commonelectrode CE.

The second circuit contact hole CCH2 may be provided in the gateinsulation layer 103, the interlayer insulation layer 105, the firstplanarization layer 110, and the second planarization layer 140overlapping a portion of the common power line CL and may expose theportion of the common power line CL. The second circuit contact holeCCH2 may be provided by removing the gate insulation layer 103, theinterlayer insulation layer 105, the first planarization layer 110, andthe second planarization layer 140 overlapping the portion of the commonpower line CL through a hole patterning process using a photolithographyprocess and an etching process. The second circuit contact hole CCH2 maybe provided along with the first circuit contact hole CCH1 and the firstelectrode contact hole ECH1.

The second electrode contact hole ECH2 may expose a portion or a wholeportion of the second electrode E2 of the light emitting device 300 andmay be provided along with the second circuit contact hole CCH2. Thesecond electrode contact hole ECH2 may be provided by removing thesecond planarization layer 140 overlapping the portion or the wholeportion of the second electrode E2 of the light emitting device 300through a hole patterning process using a photolithography process andan etching process. In this instance, the second circuit contact holeCCH2 and the second electrode contact hole ECH2 may be provided throughthe same hole patterning process as the first circuit contact hole CCH1and the first electrode contact hole ECH1.

The pixel electrode AE and the common electrode CE may be simultaneouslyprovided through an electrode patterning process using a depositionprocess of depositing an electrode material on the second planarizationlayer 140 including the first and second circuit contact holes CCH1 andCCH2 and the first and second electrode contact holes ECH1 and ECH2, alithography process and an etching process. Therefore, in the presentembodiment, since the common electrode CE and the pixel electrode AEconnecting the light emitting device 300 and the pixel circuit PC aresimultaneously formed, an electrode connection process is simplified,and a process time taken in a process of connecting the light emittingdevice 300 and the pixel circuit PC is considerably shortened, therebyenhancing a productivity of the light emitting diode display device.

The light emitting diode display device according to the presentembodiment may further include a second substrate 500.

The second substrate 500 may be disposed to cover a portion other thanthe pad part of the first substrate 100, thereby protecting a pixelarray provided on the first substrate 100. The second substrate 500 maybe defined as a color filter array substrate, an opposite substrate, oran encapsulation substrate. For example, the second substrate 500according to an embodiment may be formed of a transparent glassmaterial, a transparent plastic material, and/or the like, but is notlimited thereto.

The second substrate 500 according to an embodiment may include a blackmatrix 510.

The black matrix 510 may define an opening area of each pixel SPprovided on the first substrate 100. That is, the black matrix 510 maybe provided on the second substrate 500 overlapping a light blockingarea other than the opening area overlapping the light emitting device300 of each pixel SP, thereby preventing or reducing color mixturebetween adjacent opening areas. The black matrix 510 according to anembodiment may include a plurality of first light blocking patternswhich cover the plurality of gate lines GL, the plurality of commonpower lines CL, and the pixel circuit PC of each pixel SP, a pluralityof second light blocking patterns which cover the plurality of datalines DL and the plurality of driving power lines PL, and a third lightblocking pattern Which covers an edge of the second substrate 500. Inthis instance, the first to third light blocking patterns may beprovided on the same layer, and thus, the black matrix 510 may have amesh form.

In addition, the second substrate 500 may further include a lightextraction layer 530 provided in the opening area defined by the blackmatrix 510. The light extraction layer 530 may be formed of atransparent material and may externally extract light emitted from thelight emitting device 300. An opposite surface of the light extractionlayer 530 facing the light emitting device 300 may have a lens form forincreasing a linearity of the light emitted from the light emittingdevice 300. The light extraction layer 530 minimizes a step heightbetween the opening area and a top of the black matrix 510 provided onthe second substrate 500.

In an instance where the light emitting device 300 disposed in eachpixel SP emits white light, the second substrate 500 may include a colorfilter layer 530 provided in the opening area, instead of the lightextraction layer 530.

The color filter layer 530 may include a red color filter, a green colorfilter, and a blue color filter corresponding to respective colorsdefined in the plurality of pixels SP. The color filter layer 530 maytransmit only light, having a wavelength of a color corresponding to acorresponding pixel SP, of the white light emitted from thecorresponding pixel SP.

The light emitting diode display device according to an embodiment ofthe present disclosure may further include an encapsulation layer 160that covers a top of the first substrate 100 including the pixel SP andthe light emitting device 300.

The encapsulation layer 160 may be provided between the first substrate100 and the second substrate 500 to cover the pixel SP and the lightemitting device 300. That is, the encapsulation layer 160 may be coatedon the top of the first substrate 100 including the pixel SP and thelight emitting device 300, thereby protecting the pixel SP and the lightemitting device 300 provided on the first substrate 100. Theencapsulation layer 160 may be an optical clear adhesive (OCA) or anoptical clear resin (OCR), but is not limited thereto.

The encapsulation layer 160 according to an embodiment may be formed ofa thermocurable resin and/or a photocurable resin. The encapsulationlayer 160 may be directly coated on the top of the first substrate 100in a liquid state, and then, may be cured by a curing process using heatand/or light. In this instance, a curing process for the encapsulationlayer 160 may be performed after a process of bonding the secondsubstrate 500 to the encapsulation layer 160 coated on the top of thefirst substrate 100. The encapsulation layer 160 may buffer the press ofthe second substrate 500 in the process of bonding the second substrate500 to the first substrate 100.

The light emitting diode display device according to an embodiment ofthe present disclosure may further include a reflective layer 101disposed between the first substrate 100 and the light emitting device300.

The reflective layer 101 may be disposed between the floor surface 130 aof the concave portion 130 and the first substrate 100 to overlap thelight emitting device 300. The reflective layer 101 according to anembodiment may be formed of a material which is the same as that of thegate electrode GE of the driving TFT T2, and may be provided on the samelayer as the gate electrode GE. The reflective layer 101 may reflectlight, which is incident from the light emitting device 300, toward thesecond substrate 500. Accordingly, the light emitting diode displaydevice according to an embodiment of the present disclosure may includethe reflective layer 101, and thus, may have a top emission structure.

Optionally, the reflective layer 101 may be formed of a material whichis the same as that of the source/drain electrode SE/DE of the drivingTFT T2, and may be provided on the same layer as the source/drainelectrode SE/DE.

FIG. 5 is a diagram for describing a modification embodiment of aconcave portion illustrated in FIG. 3.

Referring to FIG. 5, a concave portion 130 according to the modificationembodiment may be provided in plurality, and the plurality of concaveportions 130 may be respectively provided to have different depths D1 toD3 in at least three adjacent pixels SP1 to SP3 configuring one unitpixel UP. That is, the concave portions 130 according to themodification embodiment may be provided to the different depths D1 to D3from the top 110 a of the first planarization layer 110, based on aheight of the light emitting device 300 disposed in a correspondingpixel, and thus, a height deviation (or a step height) between a redlight emitting device 300-1, a green light emitting device 300-2, and ablue light emitting device 300-3 is removed or minimized.

A light emitting diode display device according to the presentembodiment may include a red pixel SP1, a green pixel SP3, and a bluepixel SP2 for realizing a color image, and the light emitting device 300may be categorized into the red light emitting device 300-1, the greenlight emitting device 300-2, and the blue light emitting device 300-3and may be disposed in the concave portion 130 provided in a pixel of acorresponding color. In this instance, the red light emitting device300-1, the green light emitting device 300-2, and the blue lightemitting device 300-3 may have different heights (or thicknesses) due toa process error in a manufacturing process. For example, a thickness ofthe light emitting device 300 may be thickened in the order of the redlight emitting device 300-1, the green light emitting device 300-2, andthe blue light emitting device 300-3. In this instance, the depths D1 toD3 of the concave portions 130 according to the modification embodimentmay be progressively-deeply provided in the order of the red lightemitting device 300-1, the green light emitting device 300-2, and theblue light emitting device 300-3, based on a height of a correspondinglight emitting device.

Therefore, in the present embodiment, since the concave portions 130 ofrespective pixels are provided to the different depths D1 to D3 based ona height of the light emitting device 300 which is to be provided in acorresponding pixel, uppermost surfaces (for example, first electrodesE1) of the respective light emitting devices 300-1 to 300-3 disposed inpixels may be disposed on the same horizontal line HL, and thus, an opendefect where the first electrode E1 of each of the light emittingdevices 300-1 to 300-3 is not exposed is prevented from occurring due toa height deviation of each of the light emitting devices 300-1 to 300-3in a patterning process performed for the first and second electrodecontact holes. Also, according to the present embodiment, in the topemission structure, an optical distance between the reflective layer 101and the light emitting devices 300-1 to 300-3 disposed in respectivepixels is optimized by using the concave portions 130 which are providedto the different depths D1 to D3 in the respective pixels, and thus, areflection efficiency of the reflective layer 101 is improved, therebymaximizing a light efficiency of each of the light emitting devices300-1 to 300-3.

FIG. 6 is a diagram for describing a light emitting diode display deviceaccording to another embodiment of the present disclosure and isconfigured by adding a wavelength conversion layer to the light emittingdiode display device illustrated in FIG. 3. Hereinafter, therefore, thewavelength conversion layer and elements associated thereto will bedescribed.

Referring to FIG. 6, in the present embodiment, a wavelength conversionlayer 170 may be provided between a first substrate 100 and a secondsubstrate 500. If a light emitting device 300 emitting light of a firstcolor except white is identically disposed in each of a plurality ofpixels SP1 to SP3, the wavelength conversion layer 170 may be providedon a top of an encapsulation layer 160, for realizing a color through aunit pixel UP.

The wavelength conversion layer 170 may be provided on the top of theencapsulation layer 160 provided on the first substrate 100 and may beprovided on the encapsulation layer 160 overlapping a display area ofthe first substrate 100. For example, the wavelength conversion layer170 may be directly coated on a top of the first substrate 100 in aliquid state, and then, may be cured by a curing process using heatand/or light. As another example, the wavelength conversion layer 170may be manufactured in a sheet form and may be directly adhered to thetop of the encapsulation layer 160.

The wavelength conversion layer 170 may emit light of a second color,based on the light of the first color incident from the light emittingdevice 300 of each of the pixels SP1 to SP3. That is, the wavelengthconversion layer 170 may absorb the light of the first color and mayemit the light of the second color through re-emission. In thisinstance, the light of the first color may be blue light, and the lightof the second color may be yellow light.

The wavelength conversion layer 170 according to an embodiment mayinclude a phosphor or a quantum dot. The phosphor according to anembodiment may be a yellow phosphor which is excited by blue light toemit yellow light, and for example, may be an yttrium aluminum garnet(YAG)-based material. The quantum dot according to an embodiment may beexcited by blue light to emit yellow light and may have a size foremitting light having a yellow wavelength, and for example, may includeCdS, CdSe, CdTe, ZnS, ZnSe, GaAs, GalP, GaAs—P, Ga—Sb, InAs, InP, InSb,AlAs, AlP, AlSb, and/or the like.

The light of the second color, which is re-emitted from the wavelengthconversion layer 170 and is irradiated onto the second substrate 500,may be combined with the light of the first color which is irradiatedonto the second substrate 500 without being re-emitted from thewavelength conversion layer 170, and thus, may be converted into whitelight. The white light may be filtered by a color filter layer 530provided on the second substrate 500 to overlap each of the pixels SP1to SP3, and thus, may be emitted as color light corresponding to each ofthe pixels SP1 to SP3.

Accordingly, in the present embodiment, since the same light emittingdevices 300 are respectively disposed in the concave portions 130 of theplurality of pixels SP1 to SP3, a mounting process for light emittingdevices may be performed irrespective of pixels, and thus, a mountingprocess time taken in the mounting process for light emitting devices isshortened.

FIG. 7 is a diagram for describing a light emitting diode display deviceaccording to another embodiment of the present disclosure and isconfigured by modifying the adhesive member of the light emitting diodedisplay device illustrated in FIGS. 1 to 4. Hereinafter, therefore, theadhesive member and elements associated thereto will be described.

Referring to FIG. 7, in the present embodiment, an adhesive member 305may be coated on a top 110 a of a first planarization layer 110 and aside surface and a floor surface 130 a of a concave portion 130. Thatis, the adhesive member 305 may be provided to wholly cover a portion ofthe first planarization layer 110 other than first and second circuitcontact holes CCH1 and CCH2 provided in the first planarization layer110. In other words, the adhesive member 305 may be disposed between thefirst planarization layer 110 and the second planarization layer 140 andmay be disposed between the first planarization layer 110 and a lightemitting device 300.

The adhesive member 305 according to an embodiment may be coated on thewhole top 110 a of the first planarization layer 110, where the concaveportion 130 is provided, to a certain thickness. A portion of theadhesive member 305 coated on the top 110 a of the first planarizationlayer 110, where the first and second circuit contact holes CCH1 andCCH2 are to be provided, may be removed when forming the first andsecond circuit contact holes CCH1 and CCH2. Therefore, in the presentembodiment, immediately before a mounting process for the light emittingdevice 300, the adhesive member 305 may be coated on the whole top 110 aof the first planarization layer 110, where the concave portion 130 isprovided, to have a certain thickness, and thus, according to thepresent embodiment, a process time taken in forming the adhesive member305 is shortened in comparison with the embodiment of FIGS. 1 to 4.

In the present embodiment, the adhesive member 305 may be provided onthe whole top 110 a of the first planarization layer 110, and thus,except that the second planarization layer 140 according to the presentembodiment is provided to cover the adhesive member 305, the secondplanarization layer 140 according to the present embodiment is the sameas the second planarization layer illustrated in FIG. 3.

FIG. 8 is a diagram for describing a light emitting diode display deviceaccording to another embodiment of the present disclosure and isconfigured by removing the second substrate from the light emittingdiode display device illustrated in FIG. 3. Hereinafter, therefore,elements associated to the removal of the second substrate will bedescribed.

Referring to FIG. 8, the light emitting diode display device accordingto the present embodiment may include a cover layer 400 instead of thesecond substrate of the light emitting diode display device illustratedin FIG. 3.

The cover layer 400 may be formed to cover an encapsulation layer 160.The cover layer 400 protects each of a plurality of pixels SP andefficiently outputs light, emitted from a light emitting device 300 ofeach pixel SP, to the outside. The cover layer 400 according to anembodiment may be formed of a material having a relatively lowrefractive index. For example, the cover layer 400 may be formed of LiF,MgF₂, CaF₂, ScF₃, and/or the like and may have a multi-layer structurehaving different refractive indexes.

In addition, the light emitting diode display device according to thepresent embodiment may further include a black matrix 180 providedbetween an encapsulation layer 160 and the cover layer 400.

The black matrix 180 may define an opening area overlapping an emissivearea of each pixel SP and may be provided on a top of the encapsulationlayer 160 overlapping a light blocking area except the emissive area ofeach pixel SP, thereby preventing or reducing color mixture betweenadjacent pixels SP. Except that the black matrix 180 is directlyprovided on the top of the encapsulation layer 160, the black matrix 180may have the same shape as that of the black matrix illustrated in FIG.3 or 6, and thus, its repetitive description is not provided.

In an instance where the light emitting device 300 disposed in eachpixel SP emits white light, the light emitting diode display deviceaccording to the present embodiment may further include a color filterlayer 190.

The color filter layer 190 may be directly formed on a top of theencapsulation layer 160 overlapping the opening area defined by theblack matrix 180 and may include a red color filter, a green colorfilter, and a blue color filter corresponding to respective colorsdefined in the plurality of pixels SP. The color filter layer 190 maytransmit only light, having a wavelength of a color corresponding to acorresponding pixel SP, of the white light emitted from thecorresponding pixel SP.

In addition, in the light emitting diode display device according to thepresent embodiment, an adhesive member 305 disposed only between a floorsurface 130 a of a concave portion 130 and the light emitting device 300may be replaced with the adhesive member 305 illustrated in FIG. 7. Thatis, in the present embodiment, the adhesive member 305 may be disposedbetween a first planarization layer 110 and a second planarization layer140 and may be disposed between the first planarization layer 110 andthe light emitting device 300.

FIG. 9 is a diagram for describing a light emitting diode display deviceaccording to another embodiment of the present disclosure and isconfigured by adding a wavelength conversion layer to the light emittingdiode display device illustrated in FIG. 8. Hereinafter, therefore, thewavelength conversion layer and elements associated thereto will bedescribed.

Referring to FIG. 9, in the present embodiment, if a light emittingdevice 300 emitting light of a first color except white is identicallydisposed in each of a plurality of pixels SP1 to SP3, a wavelengthconversion layer 170 may be provided on a top of an encapsulation layer160, for realizing a color through a unit pixel UP. That is, thewavelength conversion layer 170 may be provided between theencapsulation layer 160 and each of a black matrix 180 and a colorfilter layer 190. The wavelength conversion layer 170 is the same as thewavelength conversion layer illustrated in FIG. 6, and thus, itsrepetitive description is not provided.

The black matrix 180 may be directly formed on the wavelength conversionlayer 170 overlapping a light blocking area except an emissive area ofeach of a plurality of pixels SP.

The color filter layer 190 may be directly formed on a top of thewavelength conversion layer 170 overlapping an opening area defined bythe black matrix 180 and may include a red color filter, a green colorfilter, and a blue color filter corresponding to respective colorsdefined in the plurality of pixels SP. The color filter layer 190 maytransmit only light, having a wavelength of a color corresponding to acorresponding pixel SP, of the white light emitted from thecorresponding pixel SP.

In addition, in the light emitting diode display device according to thepresent embodiment, an adhesive member 305 disposed only between a floorsurface 130 a of a concave portion 130 and the light emitting device 300may be replaced with the adhesive member 305 illustrated in FIG. 7. Thatis, in the present embodiment, the adhesive member 305 may be disposedbetween a first planarization layer 110 and a second planarization layer140 and may be disposed between the first planarization layer 110 andthe light emitting device 300.

FIG. 10 is a diagram for describing a light emitting diode displaydevice according to another embodiment of the present disclosure and isconfigured by adding a partition wall to the light emitting diodedisplay device illustrated in FIG. 9. Hereinafter, therefore, thepartition wall and elements associated thereto will be described.

Referring to FIG. 10, in the present embodiment, a partition wall 175may be directly formed on a top of an encapsulation layer 160 to definean opening area overlapping a light emitting device 300 of each of aplurality of pixels SP. That is, the partition wall 175 may be directlyformed on a top of the encapsulation layer 160 overlapping a lightblocking area except an emissive area of each pixel SP and may define anopening area of each pixel SP. The partition wall 175 prevents orreduces color mixture between adjacent pixels SP.

Since the partition wall 175 is provided on the top of the encapsulationlayer 160, the above-described wavelength conversion layer 170 may bedirectly formed on the top of the encapsulation layer 160 overlappingthe opening area of each pixel SP defined by the partition wall 175.Accordingly, in the present embodiment, the partition wall 175 preventsor reduces color mixture between adjacent pixels SP, and the wavelengthconversion layer 170 is provided on only the opening area of each pixelSP, thereby decreasing the material cost of the wavelength conversionlayer 170.

Since the partition wall 175 is provided on the top of the encapsulationlayer 160, the above-described black matrix 180 may be provide on a topof the partition wall 175 to have the same shape as that of thepartition wall 175.

In addition, in the light emitting diode display device according to thepresent embodiment, an adhesive member 305 disposed only between a floorsurface 130 a of a concave portion 130 and the light emitting device 300may be replaced with the adhesive member 305 illustrated in FIG. 7. Thatis, in the present embodiment, the adhesive member 305 may be disposedbetween a first planarization layer 110 and a second planarization layer140 and may be disposed between the first planarization layer 110 andthe light emitting device 300.

FIG. 11 is a diagram for describing a light emitting diode displaydevice according to another embodiment of the present disclosure andillustrates an example where an encapsulation layer is configured with ablack matrix and a color filter layer in the light emitting diodedisplay device illustrated in FIG. 8. Hereinafter, therefore, the blackmatrix, the color filter layer, and elements associated thereto will bedescribed.

Referring to FIG. 11, in the light emitting diode display deviceaccording to the present embodiment, a black matrix 180 may be directlyprovided on a first substrate 100 and may define an opening areaoverlapping an emissive area of each of a plurality of pixels SP. Also,the black matrix 180 fundamentally prevents or reduces color mixturebetween adjacent pixels SP, and thus, decreases a black luminance of thedisplay device, thereby enabling the display device to realize realblack. To this end, the black matrix 180 according to an embodiment maybe formed to cover a second planarization layer 140, a pixel electrodeAE, a common electrode CE, and first and second circuit contact holesCCH1 and CCH2 except a predetermined opening area and may define theopening area of each pixel SP. In more detail, except that the blackmatrix 180 is filled into each of the first and second circuit contactholes CCH1 and CCH2 and is directly formed on a top of each of thesecond planarization layer 140, the pixel electrode AE, and the commonelectrode CE, the black matrix 180 according to the present embodimentis the same as the black matrix illustrated in FIG. 7.

The color filter layer 190 may be directly formed on a top of each ofthe pixel electrode AE, the common electrode CE, and the secondplanarization layer 140 overlapping the opening area defined by theblack matrix 180 and may include a red color filter, a green colorfilter, and a blue color filter corresponding to respective colorsdefined in the plurality of pixels SP. The color filter layer 190 maytransmit only light, having a wavelength of a color corresponding to acorresponding pixel SP, of the white light emitted from thecorresponding pixel SP.

In addition, in the light emitting diode display device according to thepresent embodiment, an adhesive member 305 disposed only between a floorsurface 130 a of a concave portion 130 and the light emitting device 300may be replaced with the adhesive member 305 illustrated in FIG. 7. Thatis, in the present embodiment, the adhesive member 305 may be disposedbetween a first planarization layer 110 and the second planarizationlayer 140 and may be disposed between the first planarization layer 110and the light emitting device 300.

In the light emitting diode display device according to the presentembodiment, since the black matrix 180 is directly provided on the topof the second planarization layer 140, black luminance is reduced, andthus, real black is realized.

FIG. 12 is a diagram for describing a light emitting diode displaydevice according to another embodiment of the present disclosure andillustrates an example where an encapsulation layer is configured bymodifying a connection structure of a common electrode and a lightemitting device in the light emitting diode display device illustratedin FIG. 3. Hereinafter, therefore, elements associated to the connectionstructure of the common electrode and the light emitting device will bedescribed.

Referring to FIG. 12, the light emitting diode display device accordingto the present embodiment may include a plurality of pixels SP, a firstplanarization layer 110, a concave portion 130, a light emitting device300, a second planarization layer 140, a pixel electrode AE, a thirdplanarization layer 150, and a common electrode CE.

The plurality of pixels SP, the first planarization layer 110, theconcave portion 130, the light emitting device 300, the secondplanarization layer 140, and the pixel electrode AE are the same asthose of the light emitting diode display device illustrated in FIG. 3,and thus, their repetitive descriptions are not provided.

The third planarization layer 150 may be provided on the secondplanarization layer 140 to cover the pixel electrode AE. In thisinstance, the third planarization layer 150 may be formed of a materialwhich is the same as that of the second planarization layer 140.

The common electrode CE may be electrically connected to a secondelectrode E2 of the light emitting device 300 and may be defined as acathode electrode. The common electrode CE may be provided on the thirdplanarization layer 150 overlapping the second electrode E2 of the lightemitting device 300. The common electrode CE may be electricallyconnected to the second electrode E2 of the light emitting device 300through a second electrode contact hole ECH2 which is provided to passthrough the third planarization layer 150 and the second planarizationlayer 140.

The common electrode CE may be provided all over the third planarizationlayer 150 and may be electrically connected to the second electrode E2of the light emitting device 300. That is, the common electrode CE maybe provided in a whole display area defined on a first substrate 100 andmay be connected in common to the second electrode E2 of the lightemitting device 300 disposed in each of the plurality of pixels SP.Therefore, in the present embodiment, a resistance value of the commonelectrode CE is reduced. The common electrode CE may be formed of atransparent conductive material which is low in reflectivity.

The common electrode CE may be supplied with a common power from a paneldriver through a pad part. Furthermore, the common electrode CE may beadditionally supplied with the common power through a scan drivingcircuit. Therefore, in the present embodiment, the common power line CLand the second circuit contact hole CCH2 illustrated in FIG. 3 may beomitted.

The second electrode contact hole ECH2 may expose a portion or a wholeportion of the second electrode E2 of the light emitting device 300. Thesecond electrode contact hole ECH2 may be provided by removing thesecond planarization layer 140 and the third planarization layer 150overlapping the portion or the whole portion of the second electrode E2of the light emitting device 300 through a hole patterning process usinga photolithography process and an etching process.

The light emitting diode display device according to the presentembodiment may further include an encapsulation layer 160 that coversthe common electrode CE.

The encapsulation layer 160 may be coated on the first substrate 100 tocover the common electrode CE and the second electrode contact holeECH2, thereby protecting the pixel SP and the light emitting device 300provided on the first substrate 100. The encapsulation layer 160according to an embodiment may be an optical clear adhesive (OCA) or anoptical clear resin (OCR), but is not limited thereto.

The light emitting diode display device according to the presentembodiment may further include a second substrate 500 coupled to a topof the encapsulation layer 160.

The second substrate 500 may be disposed to cover a portion other thanthe pad part of the first substrate 100, thereby protecting a pixelarray provided on the first substrate 100. The second substrate 500 maybe defined as a color filter array substrate, an opposite substrate, oran encapsulation substrate. The second substrate 500 may include a blackmatrix 510 and a color filter layer 530. The black matrix 510 and thecolor filter layer 530 are the same as the black matrix and the colorfilter layer illustrated in FIG. 3, and thus, their repetitivedescriptions are not provided.

In addition, the light emitting diode display device according to thepresent embodiment may be configured in combination with features of thelight emitting diode display devices illustrated in FIGS. 5 to 11.

In the present embodiment, as illustrated in FIG. 5, the concave portion130 may be provided in plurality, and the plurality of concave portions130 may have different depths in respective pixels SP.

The light emitting diode display device according to the presentembodiment may further include a wavelength conversion layer 170illustrated in FIG. 6, and the wavelength conversion layer 170 may beprovided between the encapsulation layer 160 and the second substrate500.

In the present embodiment, an adhesive member 305 disposed only betweena floor surface 130 a of the concave portion 130 and the light emittingdevice 300 may be replaced with the adhesive member 305 illustrated inFIG. 7. That is, in the present embodiment, the adhesive member 305 maybe disposed between the first planarization layer 110 and the secondplanarization layer 140 and may be disposed between the firstplanarization layer 110 and the light emitting device 300.

The light emitting diode display device according to the presentembodiment, as illustrated in FIG. 8, may include a black matrix 180 anda color filter layer 190, which are provided on a top of theencapsulation layer 160, and a cover layer 400 which covers the blackmatrix 180 and the color filter layer 190, instead of the secondsubstrate 500 bonded to the encapsulation layer 160. Furthermore, thelight emitting diode display device according to the present embodimentmay further include the wavelength conversion layer 170 illustrated inFIG. 9, and moreover, may further include the partition wall 175illustrated in FIG. 10.

The light emitting diode display device according to the presentembodiment, as illustrated in FIG. 11, may include the black matrix 180and the color filter layer 190, instead of omitting the encapsulationlayer 160.

FIG. 13 is a diagram for describing a light emitting diode displaydevice according to another embodiment of the present disclosure andillustrates an example where the light emitting diode display deviceillustrated in FIG. 12 is configured as a bottom emission type.Hereinafter, therefore, elements associated to the bottom emission typewill be described.

Referring to FIG. 13, the light emitting diode display device accordingto the present embodiment may be configured by removing the black matrixand the color filter layer, which are provided on the second substrate500, and the reflective layer 101 from the light emitting diode displaydevice illustrated in FIG. 12, and a common electrode CE may be formedof a light reflection conductive material.

In the present embodiment, the common electrode CE may be formed of thelight reflection conductive material which is high in reflectivity. Forexample, the common electrode CE may be formed of a single layer,including Al, Ag, Au, Pt, Cu, and/or the like, or a multilayer includinga plurality of the single layers which are stacked.

Moreover, in the present embodiment, the second substrate 500 may beformed of a metal material, and the black matrix and the color filterlayer provided on the second substrate 500 may be omitted. In thisinstance, a light emitting device 300 disposed in each pixel SP may emitlight of a color corresponding to a color of a corresponding pixel.

Moreover, in the present embodiment, the reflective layer 101 providedon the first substrate 100 may be omitted for bottom emission.

Since the common electrode CE provided in a whole display area is formedof the light reflection conductive material, the light emitting diodedisplay device according to the present embodiment may display an imagein the bottom emission type.

As described above, according to the embodiments of the presentdisclosure, a process time taken in a process of connecting a lightemitting device to a pixel circuit is considerably shortened, and thus,a productivity of light emitting diode display devices is enhanced.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the spirit or scope of the disclosures. Thus, itis intended that the present disclosure covers the modifications andvariations of this disclosure provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A display device comprising: a substrate; a gateline and a data line on the substrate; a pixel connected to the gateline and the data line and including a thin film transistor (TFT) on thesubstrate; a planarization layer on the TFT; and a light emitting deviceincluding a first electrode and a second electrode, wherein the lightemitting device comprises a first portion and a second portion oppositeto the first portion, the first portion including the first and secondelectrodes, wherein the TFT comprises a gate electrode, a semiconductorlayer, a source electrode, and a drain electrode, and wherein the firstportion of the light emitting device is not overlapped with the TFT. 2.The display device of claim 1, wherein the planarization layer includesat least one step portion.
 3. The display device of claim 1, wherein thelight emitting device is surrounded by the planarization layer.
 4. Thedisplay device of claim 1, further comprising an adhesive member betweenthe substrate and the light emitting device.
 5. The display device ofclaim 1, further comprising a reflective layer between the substrate andthe light emitting device.
 6. The display device of claim 5, wherein awidth of the reflective layer is greater than a width of the lightemitting device.
 7. The display device of claim 1, further comprising:an adhesive member between the substrate and the light emitting device;and a reflective layer between the substrate and the adhesive member. 8.The display device of claim 1, wherein a distance between the firstportion and the substrate is greater than a distance between the secondportion and the substrate.
 9. The display device of claim 1, wherein theplanarization layer covers the light emitting device, except for areasassociated with the first and second electrodes.
 10. The display deviceof claim 1, further comprising a black matrix defining an opening areaoverlapping with the light emitting device, wherein the planarizationlayer includes a contact hole overlapping with the TFT, and wherein theblack matrix is provided in the contact hole.
 11. The display device ofclaim 10, further comprising a color filter layer on the opening area.12. The display device of claim 10, further comprising: a color filterlayer on the opening area; and a cover layer covering the black matrixand the color filter layer.
 13. The display device of claim 1, furthercomprising: a pixel electrode electrically connected to the TFT and thefirst electrode of the light emitting device; and a common electrodeelectrically connected to the second electrode of the light emittingdevice.
 14. The display device of claim 13, wherein the planarizationlayer includes a contact hole overlapping with the TFT, wherein thepixel electrode is electrically connected to the TFT through the contacthole.
 15. The display device of claim 13, wherein the planarizationlayer comprises: a first planarization layer on the TFT; and a secondplanarization layer on the first planarization layer, wherein the pixelelectrode and the common electrode are on the second planarizationlayer.
 16. The display device of claim 13, wherein: the pixel electrodeis electrically connected to the first electrode of the light emittingdevice through a first electrode contact hole, the common electrode iselectrically connected to the second electrode of the light emittingdevice through a second electrode contact hole, and the first electrodecontact hole and the second electrode contact hole have differentdepths.
 17. The display device of claim 1, further comprising: a drivingpower line on the substrate and supplying a pixel driving power to thepixel; a common power line on the substrate and supplying a common powerto the second electrode of the light emitting device.
 18. The displaydevice of claim 1, wherein the light emitting device is a light emittingdiode device or a light emitting diode chip.
 19. The display device ofclaim 1, further comprising an insulating layer between the sourceelectrode of the TFT and the planarization layer.
 20. The display deviceof claim 1, wherein the planarization layer comprises: a firstplanarization layer on the TFT; a second planarization layer on thefirst planarization layer; and an adhesive member between the firstplanarization layer and the second planarization layer, wherein thelight emitting device is embedded or surrounded by the adhesive memberand the second planarization layer.